Television receiver



,May 10, 1932. R. D. KELL TELEVIS ION RECEIVER Filed April 1, i930 Inventor". Rag D.Ke11,

H is Attorneg;

Patented May 10, 1932 PATENT @FFEQE RAY D. KELL, OF SCOIIA, NEW YORK, AS

SIGNOR TO GENERAL ELECTRIC CGZJIPANY,

A CORPORATION OF NEW YORK TELEVISION RECEIVER Application filed April 1,

My invention relates to television receiving apparatus and it is an object of my invention to provide an improved apparatus of this character which shall avoid certain limitations introduced by flicker and brilliancy common to television apparatus heretofore employed.

My invention will be better understood from the following description taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

Referring to the drawing in which the single figure illustrates in a more or less diagrammatic manner one embodiment of my invention, I have shown at 1 a screen upon which is received the picture or view being transmitted. Light for the illumination of the screen is furnished by the lamp 2 which for example may be an electric arc. Light from lamp 2 passes successively through the condenser lenses 3, the polarizer at which may be any suitable means, for example a Nicol prism where the light becomes polarized in one plane and thence through the transpar ent electrode 5 which. for example, may be alcohol, to the member 6. This member which is shown as a plate in contact with the transparent electrode 5 comprises a suitable material which becomes double refracting when placed under electric strain, an example of such a. material being Rochelle salt. Cooperating with the plate 6 are a series of m0vable electrodes 8 carried by the disk 9 and V having uniformly varying lengths, the end of each being turned toward the plate, whereby at each rotation of the disk the electrostatic field between the ends of the electrodes 8 and the plate 6 scan or cover a prescribed portion of the plate in a manner similar to scanning arrangements heretofore employed in television apparatus. The disk 9 is shown mounted on the shaft of the driving motor 10 by which the disk is rotated in synchronism with the sending apparatus. The disk is also shown having the hub or slip ring 11 which is engaged by the brush 12. Beyond the plate 6 and the moving electrodes 8 is the analyzing means 14:, for example a Nicol prism, which is turned at right angles to the polarizer 4.

1930. Serial No. 440,845.

The objective lens 15 arranged beyond the prism 14 serves to produce an image of plate 6 upon the screen 1. The signal from the sending station may be transmitted in any desired manner. In the illustration I have shown at 16 apparatus for receiving an amplifying a signal sent by radio, connections being made therefrom by the conductors 17 to the fixed electrode 5 and to the moving electrodes 8 through the brush 1), slip ring 11 and disk 9.

hen no signal is being received from the sending station, the screen is dark inasmuch as the polarizer and analyzer are turned so that no light is passed to the screen when the plate 6 is not under electric strain. When the signal is being received, successive portions of the plate 6 are subjected to an electric strain which is variable in accordance with the received signal. By reason of the double refractory property of the plate when under strain, the successive portions of the plate when viewed through the analyzer 14L appear to become luminous, the luminosity varying with the intensity of the received signal. By the use of the objective 15 a magnified image of the plate 6 is produced on the screen 1. An important property of the plate 6 is that it requires an appreciable time interval to recover from the electric strain thus prolonging the time during which each successive area thereof appears to be luminous and accordingly increasing the brightness of the image. For example, if pictures are being sent at the rate of sixteen per secend, the plate 6 may be constructed to require nearly a sixteenth of a second to recover. Hence the screen at any instant will show substantially a complete picture rather than a single picture element. A variation in the time of recovery may be effected by varying the temperature of the plate.

I have shown the particular embodiment described above as illustrative of my invention and it will be apparent that various modifications may be made without departing from the spirit and scope of my invention which modifications I aim to cover by the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. Television receiving apparatus comprising a member which becomes double refracting when put under electric strain, op-

tical means. associated therewith for rendering visible those portions thereofsubjected to electric strain, and means for sub ecting points of themember. successively to electric strain varied'in accordance with the received signal.

2. Televlsion receiving apparatus com prising a member including a material which is double refracting whenput under; electric:

' liaving'tlieir a-Xesarranged at substantially right angles, a member therebetween'which becomes double refracting when put under electritrstrain', scanning means for" subj ectiirg points of said member-successively to elec t'ric strain, means= for" projecting' light through the polarizing means and said memher; .a nd=means=forapplyingto sai d scanning means a potentialvariable in accordance with the received signal.

4:. Television receiving apparatus comprising a member whicli'becolnes' double refracting when-subjectedtoeleetric strain, optical means-associated 1 with sai d' member for rendering visible thoseportions thereof "subj e'ct ed to'such strain, scanning means comprising a plurality of electrodes-for applying electric strain successively'to points of the" member, and means=fonapplying a varying potential to theielectrodes in' accordance witlr the i received signallv 5:- Telev'ision'receivingapparatus comprislightsource; a member which-becomes double retracting-when subj ected' to i electric strain arranged'in the'path-of light'from said source-,uar plurality of. polarizingrdevi ces are rangedlwithtthein planes of) polarization: at right1angles=to:each others-and ilocatedzat op.- positee sides of said: memberand scanning means comprising av plurality of. movable electrodes for applying electric strain succes= sively tmpOrtiOns of the member, and means for applying to said electrodes a; potential Whichwaris' in iaccordancelwitlrtlie received signal:

6. Television receiving apparatus comprising, alight source,,a plate comprising Rochellesalt arrangedin the path oflight from saidlsource; Nicolprisms arranged on opposite sides of said plate and turned relatively to each other to cut off all'liglit tending to pass therethrough, a transparent electrode in contact with one face of said plate, a rotatable member having a series of electrodes adapted to scan the plate, a screen, and means for imaging the plate on the screen.

7. Television apparatus-comprising aplate ofmater-ialwhicli becomes-double refracting when ubjected to electric strain, optical means for projecting a beam of polarized lighttlirough'the plate at rightangles there to and scanning-means arranged progressive 131 to subject small portions of the plate successively to electric strain varied in accordance with-thereceived signal.

8. Television apparatus comprising a plate of materi wliiclrbecomes double-retracting when" subjected to electric strain, optical means for: projecting at beam of: polarized liglitthroughzthe :plate at: right angles there-'- to and seaimingrmeanscomprising" an electrode: arranged to movezoverthe face-of; the plate and to subject successive portions ofltlie. plateto: electric: strain.

9:. Television 13,131) ara-tus comprisingnplate of material which becomes double refraeting. when: subjected to electric strain, optical means for projecting a beam of polarized lightathroughithe plate-ah right anglesthereto" and scanning: means; comprising a: I'Ottltr able inemben having mpluralityof electrodes of progressively varying length arranged to movciover'the :face ofLtheplate-a-ndto subjectsuccessive smallareas" thereof to electric strain.

In Witness whereof, I have hereunto set my hand' this- 31st .day- 0M&IC-l1,.1930.-

RAY D..KELL.- 

